Possible Causes
WARNING: This page is about a different car, the 2004 Ford Econoline. However, it is still accessible from the selected car via links, so may be relevant.
An air bag tone warning indicator circuit short to battery fault can be caused by damaged wiring, terminals or connectors, faulty instrument cluster or faulty RCM.
- Check for hard or intermittent DTC
Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Retrieve and record any continuous DTCs. See RETRIEVING FAULT CODES . Perform on-demand self-test. See ON-DEMAND SELF-TEST under DIAGNOSTICS. If DTC B1891 was retrieved during on-demand self-test, fault is hard. Go to next step. If DTC B1891 was not retrieved, fault is intermittent. Go to step 5 . - Check air bag tone warning indicator circuit for short to battery
Turn ignition switch to OFF position. Disable air bag system. See DISABLING SYSTEM under DISABLING & ACTIVATING AIR BAG SYSTEM. Access RCM and disconnect harness connector C310A. See RESTRAINTS CONTROL MODULE (RCM) under REMOVAL & INSTALLATION. Access instrument cluster and disconnect connector C220B. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. See Fig 1 . Turn ignition switch to ON position. Measure voltage between ground and harness side RCM connector C310A, terminal No. 23 (Light Blue/Pink wire, circuit No. 1083). If voltage is less than 0.2 volt, go to next step. If voltage is more than 0.2 volt, repair short to battery in Light Blue/Pink wire. See WIRING DIAGRAMS . Go to step 6 .NOTE: Due to open circuit in Light Blue/Pink wire, DTC B1892 should be retrieved when carrying out on-demand self-test in next step. DTC B1891 should not be retrieved at this time. - Check air bag tone warning indicator
Turn ignition switch to OFF position. Reconnect RCM harness connector C310A. Turn ignition switch to ON position. Turn ignition switch to ON position. Perform on-demand self-test. If DTC B1891 was retrieved during on-demand self-test, replace, go to next step. If DTC B1891 was not retrieved during on-demand self-test, replace instrument cluster. Go to step 6 .NOTE: Ensure all air bag system simulators, sensor electrical connectors and RCM electrical connectors are connected prior to carrying out on-demand self-test, or erroneous faults may be set. - Confirm RCM fault
Turn ignition switch to OFF position. Reconnect instrument cluster harness connector C220B. Reconnect RCM connector C310A. Turn ignition switch to ON position. Perform on-demand self-test. If DTC B1891 was retrieved during on-demand self-test, replace RCM. Go to step 6 . If DTC B1891 was not retrieved during on-demand self-test, fault is intermittent. Attempt to recreate fault by flexing wire harness and cycling ignition frequently. See WIRING DIAGRAMS . Repair any intermittent problems found. Go to step 6 . - Check for intermittent fault condition
Turn ignition switch to OFF position. Disable air bag system. See DISABLING SYSTEM under DISABLING & ACTIVATING AIR BAG SYSTEM. Perform on-demand self-test. If DTC B1891 was retrieved during on-demand self-test, check for cause of intermittent fault in Light Blue/Pink wire (circuit No. 1083). See WIRING DIAGRAMS . Repair any intermittent faults found. If intermittent faults are found and corrected, go to next step. If intermittent faults are not found, go to step 2 . If DTC B1891 was not retrieved during on-demand self-test, attempt to recreate fault by flexing wire harness and cycling ignition switch frequently. Repair any intermittent problems found. Go to next step. - Check for additional DTCs
Refer to continuous DTCs recorded in step 1 . If any continuous DTCs were retrieved, go to diagnostic trouble code identification table for direction to appropriate test. See DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION table. DO NOT clear any DTCs until all DTCs have been resolved. If no continuous DTCs were retrieved, reconnect air bag system. Activate air bag system. See ACTIVATING SYSTEM under DISABLING & ACTIVATING AIR BAG SYSTEM. Clear all DTCs. See CLEARING FAULT CODES under DIAGNOSTICS.